In order to determine the actual positions of the movable parts of a computer-controlled processing machine, it is known, for instance, in the case of machine tools or industrial robots, to couple an actual position transmitter, such as an incremental transmitter, directly or indirectly to each movable machine part. The pulses delivered by each transmitter are then added up as an actual position or distance value in a suitable computer control. The added-up actual distance values accumulated during the respective sampling periods of the position control system are then compared at the appropriate sampling instant in a known manner with reference values in the computer control. From the comparison results, the computer control then forms positioning commands for the drives of the movable machine parts. The instant processing in the computer control can be performed at a fixed clock cycle, for instance, every two milliseconds.
Problems arise, however, in high-resolution measuring transmitters, such as, incremental measuring transmitters with pulse multiplication, in which the transmission frequency rises up into the megahertz range. The transmission of serial pulses with the position information to the computer control for summation and comparison via data lines then becomes extremely critical as to disturbances and switching elements. The use of high frequency interference suppression and decoupling are relatively costly solutions to the problem.
It is thus an object of the present invention to make provision in a position control system, in which electrical pulses with a high frequency are supplied by actual position transmitters, that conventional transmission lines can be used without special arrangements.